SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81fafe35821ded383bcd537239765694ce3639c21d25ae4b5d84ef7f34b666d9' 
  AND token = 'Cj2KKXPgQ8ZEqQXCCzQ60ENS0mq2KJEWvZK9DsAlVSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}